1. Field of the Invention
The embodiment of the present invention relates to an apparatus and method for controlling operation of a light emitting diode (LED) in a light unit.
2. Description of the Related Art
In recent years, LEDs are widely used as a light source of a backlight unit for a liquid crystal display (LCD) panel to enhance color reproduction and obtain high brightness.
The backlight unit can be classified into an edge-type backlight unit and a direct-type backlight unit according to the method of using the light source. In the edge-type backlight unit, a light source is installed at the side of a light guide plate. The edge-type backlight unit has been applied to a relatively small-sized LCD device such as a handy terminal, while the direct-type backlight unit has been applied to medium and large-sized LCD devices larger than 20 inches.
In such a backlight unit, a plurality of LEDs each provided with red (R), green (G) and blue (B) LED chips are arranged in an array configuration. The same color LED chips are connected in series between the LEDs. Driving pulses are supplied to the LED chips, and white light obtained by mixing red, green and blue lights. THE red, green and blue light generated by the supply of the driving pulses is used as a light source for the backlight unit.
However, all chips of LEDs in the backlight unit are simultaneously turned on or off. When simultaneously turned on, synthetic harmonic waves are so much generated between the LED chips, so that wave noise may occur on a screen of an LCD panel. Consequently, the wave noise may distort a phase made on the LCD panel to deteriorate the quality of an image.